public class Test {
    public static void main(String[] args) {
        //计算1/1-1/2+1/3-1/4+1/5 …… + 1/99 - 1/100 的值
       float sum=0;
        for( int i = 1; i <=100 ; i++) {
            if(i%2==0){
                sum-=1.0/i;
            }
              else{
                  sum+=1.0/i;
            }

        }
        System.out.println("sum="+sum);
    }
}
